using System;
using System.Collections.Generic;
using System.Text;

namespace PlayerSampleMission1CSharp
{
    public abstract class FSMState
    {
        protected object owner = null;

        public FSMState(object owner) {
            this.owner = owner;
        }

        public object Owner
        {
            get { return owner; }
            set { owner = value; }
        }

        public abstract void Enter();
        public abstract void Exit();
        public abstract void Update();
        public abstract Type getNextTransition();
    }

    public class FSMMachine
    {
        // Déclaration of the variables
        protected List<FSMState> states = new List<FSMState>(5); // List of all the states
        protected FSMState currentState = null;  // Current state
        protected FSMState defaultState = null; // state by default

        public void AddState(FSMState state) { states.Add(state); }
        public void SetDefaultState(FSMState state) { this.defaultState = state; }
        public FSMState getCurrentState() { return this.currentState; }

        private FSMState existsState(Type type) {
            foreach (FSMState state in states) {
                if (state.GetType() == type)
                    return state;
            }
            return defaultState;
        }

        public void Update()
        {
            // If there is at least one state
            if (states.Count != 0)
            {
                // If it is the first iteration
                if (currentState == null)
                {
                    // current state = default state
                    currentState = defaultState;
                    // even default state was not define
                    if (currentState == null)
                        // we stop
                        return;
                }

                Type oldStateType = currentState.GetType();
                Type newStateType = currentState.getNextTransition();

                // If the state has changed
                if (oldStateType != newStateType)
                {
                    currentState.Exit(); // exit the current state
                    currentState = existsState(newStateType); // go to the next state
                    currentState.Enter(); // enter the state
                }
                // update the state
                currentState.Update();
            }
        }
    }
}